1. Field of the Invention
The present invention relates to a hot water type first idle control device utilizing cooling water for an engine and particularly, to an improvement in a hot water type first idle control device comprising a first idle adjusting member for adjusting the first idling state of an engine, and a temperature-sensitive operating device including a wax case having a wax encapsulated therein, a device housing in which the wax case is accommodated and retained, and a heating chamber through which the cooling water for the engine is allowed to flow to heat the wax, the temperature-sensitive operating device operating the first idle adjusting member in response to a thermal expansion of the wax.
2. Description of the Related Art
Such first idle control devices are conventionally known, as disclosed in Japanese Patent Application Laid-open No.64-29659, for example.
It should be noted here that in such conventionally known first idle control device, the inside of the device housing is formed as the heating chamber, and the wax case is disposed in the heating chamber, as disclosed in the above publication. Therefore, it is necessary to form each of various portions within the wax case into a liquid-tight structure in order that hot water flowing through the heating chamber may be prevented from entering into various portions within the device housing such as the wax case. Therefore, the number of parts is increased and hence, it is difficult to reduce the cost.
Accordingly, the present invention has been accomplished in view of the above circumstances, and it is an object of the present invention to provide a hot water first idle control device, wherein the wax case can be heated, while preventing of the entering of the hot water into the device housing, whereby a special liquid-tight structure is not required for each of the various portions within the device housing.
To achieve the above object, according to a first aspect and feature of the present invention, there is provided a hot water type idle control device comprising a first idle adjusting member for adjusting the first idling state of an engine, and a temperature-sensitive operating device including a wax case having a wax encapsulated therein, a device housing in which the wax case is accommodated and retained, and a heating chamber through which the cooling water for the engine is allowed to flow to heat the wax, the temperature-sensitive operating device operating the first idle adjusting member in response to the thermal expansion of the wax, wherein the heating chamber is integrally defined in the device housing to adjoin the wax case with a partition wall interposed therebetween for separating the heating chamber from the inside of the device housing.
Meanwhile, the first idle adjusting members correspond to a piston valve 11 and a bypass valve 45 in embodiments of the present invention, which will be described hereinafter.
With the first feature, when the temperature in the heating chamber through the cooling water for the engine is passed is raised with raising of the temperature of the cooling water, a heat in the heating chamber can be propagated through the partition wall to wax to expand the wax, thereby reliably operating the first idle adjusting members. Moreover, the heating chamber is separated from the inside of the device housing and hence, it is possible to reliably prevent the water flowing through the heating chamber from entering into the device housing without employment of a special liquid-tight structure for each of various portions within the device housing, and it is possible to simplify the construction of the temperature-sensitive operating device to an extent corresponding to the unnecessity of the liquid-tight structure to provide a reduction in cost.
According to a second embodiment of the present invention, in addition to the first feature, the device housing is integrally formed with a hose joint for connecting a hose for guiding the cooling water for the engine to bring the hose into communication with the heating chamber.
With the second feature, it is possible to reduce the number of parts to contribute to the further simplification of the construction of the temperature-sensitive operating device.
According to a third embodiment of the present invention, in addition to the first or second feature, the heating chamber is provided with an orifice for limiting the flow rate of water.
With the third feature, the flow rate of water in the heating chamber can be limited properly by selecting a bore diameter of the orifice, thereby controlling the speed of thermal expansion of the wax, i.e., the operational speed of the first idle adjusting members.
The above and other objects, features and advantages of the invention will become apparent from the following description of the preferred embodiment taken in conjunction with the accompanying drawings.